Apparatus for dampening a printed web



Aug. 3, 1965 H. J. SCHULTZ APPARATUS FOR DAMPENING A PRINTED WEB 5 Sheets-Sheet 1 Filed Feb. 10, 1964 yer TOR. 0% d/% WM a Aug. 3, 1965 H. J. SCHULTZ 3,193,199

APPARATUS FOR DAMPENING A PRINTED WEB Filed Feb. 10, 1964 5 Sheets-Sheet 2 m IN Aug. 3, 1965 H. J. SCHULTZ APPARATUS FOR DAMPENING A PRINTED WEB 5 Sheets-Sheet 3 Filed Feb. 10, 1964 INVENTOR.

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United States Patent 3,198,199 AFPARATUES DAMPENiNfi A PRENTFJD WEB Herman ll. Schultz, 124% W. Morse Ave, QIhieago, Ell.

Filed Feb. 1%, 1964, Ser. No. 343,616 3 Claims. (Cl. 134-122) This invention relates generally to sheet-handling apparatus and relates more particularly to auxiliary devices for use with printing presses.

In one specific aspect, the present invention relates to apparatus for dampening a printed web.

In high speed printing operations, an oven is commonly interposed between the presses and either a folding or a sheeting machine in accordance with the specific printing operation involved. The freshly printed web passes through this oven in order that the ink may be dried suihciently to avoid smudging and smearing dur ing the subsequent processing. While drying the inks, these ovens also dehydrate the paper, frequently reducing the moisture content from a normal value of to 6 percent to a value of 1 /2 to 2 percent. When it is this dry, paper is brittle and breaks easily making press operations more intermittent than continuous. Very dry paper is also difficult to fold successfully; and static electrical charges tend to develop when dry paper rubs over itself or over some other surface, thus making the neat stacking of individual sheets almost impossible.

Moistening devices have been provided heretofore in an attempt to restore the dried web to its original water content. However, these prior art devices have not completely solved the problem. Steam cabinets have been employed; but these arrangements are inherently bulky and have required relatively low press speeds if adequate moisture was to be built up in the web. More rapid wetting has been achieved with banks of spray nozzles. However, spray nozzles tend to clog with deposits of salts from the water. Moreover, uniform moistening of a moving web cannot be readily achieved using spray nozzles because the nozzles must be spaced in order to accommodate their fan-shaped or cone-shaped discharge.

Therefore, an important objection of the present invention is to provide new and improved dampening apparatus for use in a printing operation.

Another object of the invention is to provide a compact dampening apparatus that rapidly applies a uniform amount of water to a printed web.

Still another object of the invention is to provide a non-clogging dampening apparatus for use in a printing operation.

A further object of the invention is to provide dampening apparatus that promotes economy in a printing operation.

A more general object of the invention is to provide a novel device for applying a liquid to a moving sheet.

These and other objects and features of the invention will become more apparent from a consideration of the following descriptions.

Apparatus in accord with the invention includes a liquid reservoir and a rotatable cylinder disposed partly within the reservoir for receiving a film of liquid therefrom. The rotatable cylinder is also disposed partly extending from the reservoir for presenting the film of liquid at a dispensing region. Apparatus in accord with the invention additionally includes a rotatable member aligned parallel with the rotatable cylinder and having a multiplicity of flexurally resilient bristles mounted on it to extend in substantially radial directions. The rotatable member is located so as to situate the bristles in engagement with the cylinder at the dispensing region. Drive means are provided for rotating the bristle-carrying member relative to the liquid-carrying cylinder in order to sweep the bristles through the film of liquid and out of engagement with the cylinder for spattering a stream of droplets onto a web moving passed the dispensing region.

In order that the principles of the invention may be readily understood, a single embodiment thereof, applied to dampening apparatus for a printing operation but to which the application is not to be restricted, is shown in the accompanying drawings wherein:

FIG. 1 is a schematic veiw in side elevation of a lithographic printing system incorporating dampening apparatus constructed in accord with the invention;

FIG. 2 is an enlarged, side elevational view showing the passage of cut sheets from the sheeter device to the jogging device of FIG. 1;

FIG. 3 is an enlarged perspective view of the dampenin g apparatus employed in the system of FIG. '1;

FIG. 4 is an enlarged plan view partially in crosssection showing the dampening apparatus of FIG. 3;

FIG. 5 is a slightly enlarged, elevational view taken substantially along the line 5-5 of FIG. 4;

FIG. 6 is a slightly enlarged, elevational view taken substantially along the line 66 of FIG. 4;

FIG. 7 is a schematic, intermediate scale view of the dampening apparatus, showing its relationship with the chill rolls employed in the printing system of FIG. 1;

FIG. 8 is an enlarged, elevational view showing the interaction of the water supply rolls and the brush rolls used in the dampening apparatus of the invention; and

FIG. 9 is a fragmentary perspective view of the printed web, showing the uniform application of water droplets which is achieved by the dampening apparatus of the invention.

Referring now in detail to the drawings, specifically to FIG. 1, a lithographic printing system indicated generally by the numeral 24) will be seen to include, as an initial component, a supply roll arrangement 22 which comprises a paper web 24 which is Wound on a suitable core 25. The core 26 is mounted for rotation on a standard 28; and the web 24 proceeds in sequence from the supply roll arrangement 22 through an offset lithographic printing press 30, a drying oven 32, a chill roll arrangement 34, dampening apparatus 36, and a sheeter device 38 to terminate as stacked sheets at a jogging station 40.

The printing press 30 includes opposed drums 4- 2 and 44 which have cylindrical printing plates mounted on their respective surfaces for transferring inked images to the web 24 that passes therebetween. In accordance with conventional lithograiphing printing techniques, inking rolls 46 are employed in the press 30 for delivering metered quantities of ink to the plates mounted on the drums 4 2 and 44. It is realized that the press 30 may be replaced by a press that is adapted to print only one side or it may be replaced by a number of presses printing several colors on one or both sides as is desired. Furthermore, the offset lithographic printing press 30 may be replaced by a rotogravure printing press without departing from the invention.

The web 24 is drawn through the drying oven 32 by act-ion of the chill roll arrangement 34, tension rolls 48 being provided at the inlet side of the drying oven for holding the web relatively taut. The oven 32 is preferably of the gasafired type and is fashioned with a passageway 50 for the web 24. The oven 32. is also provided with flame jets or nozzles 52 which are disposed in thermal communication with the passageway 50. Ordinarily, the oven 32 is maintained at a temperature of from 400 to 500 F.; and a web entering the oven at ambient temperature frequently exits at a temperature of approximately 300 F. Furthermore, the web entering the oven has a normal moisture content of approximately 5 to 6 percent by weight; and this is commonly reduced and in compliance with an important feature of the in-,

vention, the dampening apparatus 36 is situated closely adjacent the chill roll arrangement 34 so that the dampening apparatus will operate with a relatively wanm web. Accordignly, the water applied to the web by the dampen ing apparatus 36 penetrates the web more deeply and is dispersed more uniformly throughout the fibers of the web. As the web 24 exits from the dampening apparabus 36, it has a temperature of about 80 to 100 F., and its surface is wet to the touch.

The dampening apparatus 36 is employed in replenishing a large proportion of the water that is withdrawn from web 24 [by the drying oven 32; and correspondingly, the strength of the paper and its resistance to cracking are restored with the moisture. Thus, the web 24 is ready for final processing after it leaves the dampening apparatus 36. After it has passed through the dam'pen ing apparatus, the web 24 may be directed into a folding machine, not shown, or it may be conveyed to a sheeting device and jogging station in compliance with the illustrated embodiment. It has been mentioned that the surface of the web 24 is wet to the touch upon leaving the dampening apparatus; and when the dampening apparatus is disposed clolsely adjacent the chill roll arrangement, the Web will be dry to the touch approximately twenty-live feet downstream from the dampening apparatus, assuming customary press speeds.

In the sheeter device 38, the web 24 is cut into individual sheets 58; and these individual sheets are stacked at the jogging station 46 using jogging plates or bars 66 in compliance with conventional practices. The sheets 58 are stacked on a skid 62 for subsequent transfer and storage. Considering that the Web 24 enters the sheeter device .38 at full press speed, for example a speed on the order of 800 feet .per minute, and considering that the sheets which are cut from the web come to a complete stop at the jogging station 40, it will be appreciated that considerable friction is encountered by the individual sheets. Turning to FIG. 2 for the movement, a sheet 58a which is coming to relst in the stack at the jogging station common-1y will have a speed of movement that is only one-sixth as great as the speed of movement of a sheet 581) which has been just severed from the web. It has been found that the moisture added to the web by the dampening apparatus 36 substantially eliminates the development of static electricity as the sheets 58 slide over each other. This same static problem obtains when a folder device is substiuted for the sheeter and jogger, and the dampening apparatus of the invention is equally efficacious in such a modified printing system.

The construction and operation of the dampening apparatus 36 will now be described. With reference first to FIGS. 3 and 7, the dampening apparatus will be seen to comprise liquid delivery means and liquid dispensing means. The liquid delivery means includes a water reservoir 6'4 and a pair of laterally spaced fountain rolls 66 and 68 which are individually disposed partially within the reservoir 64 for receiving a film of water therefrom and which are disposed partially extending from the reservoir for presenting a film of water at a dispensing region 70. On the other hand, the liquid dispensing means includes a pair of laterally spaced cylinders or elongated drums 72 and 74 which are associated respectively with the fountain rolls 66 and 68 and which are covered with flexu-ra lly resilient elements 76. In operation of the dampening apparatus 36, the fiexur-al-ly resilient elements 76 are caused to move over the surfaces of the corre- 4- sponding fountain rolls to spatter a stream of water droplets onto the web 24 which is moving between the drums 72 and 7 4.

Considering FIG. 7 in conjunction with FIG. 4, the water reservoir 64 is seen to be fabricated as a pair of elongated trays 7'8 and 80 which are spaced laterally to define a walled slot 32, slot 82 accommodating the passage of the web 24 through the body of the water reservoir. In compliance with a feature of the invention, connection means are provided for coupling the trays 78 and 8t? beneath the water level thereof; and these connection means take the form of return end sections 84 and 86, best seen in FIG. 4-. It is recognized that tubes or conduits of various sorts may be used in place of the re turn end sections 84 and 86. Water is conducted tothe reservoir 64 through a supply line 88, and the flow is controlled by a valve 96 which is operated by an imperforate float vessel 92. Returning to a consideration of FIGS. 3 and 7, the movement of the web 24 through the walled slot 82 is shown to be directed by means including idler rolls 94 and 96 which are suitably mounted to the framework 56.

With reference to FIG. 8, the elongated drums 72 and 74 are seen to be of similar construction, being fabricated from a tubular element 98 that i mounted for rotation about its longitudinal axis on a shaft 100. As is shown in FIG. 4, end caps 162 close the opposite ends of the tubular member 98, and the opposite ends of the shafts 160 are received in suitable journals. The showing of FIG. 4 also illustrates the fact that the drums 72 and 74 are aligned in laterally spaced relationship with their longitudina. axes disposed parallel.

The flexurally resilient element 76 which define the working surfaces of the drums 72 and 74 advantageously comprise moderately short, stiff bristles which are suitably mounted on the tubular member 98 to extend substantially radially therefrom. In the illustrated embodiment, these bristles are approximately three-quarters of an inch long, are fabricated from a polyamide resin such as nylon, and are arranged on the tubular member 98 in a dense pattern. The elements 76 cover the entire peripheral surface of the tubular member 98 to define a cylindrical brush at least as long as the web 24 is wide whereby the droplets spattered onto the web by the bristles are distributed on the web uniformly. correspondingly, the fountain rolls 66 and 68 are of a length at least a great as the width of the web for delivering a uniform supply of water to the bristles for dispensing. In order that the fountain rolls 66 and 68 may efiiciently transfer a film of water from the tanks '78 and 8%) respectively to the bristle-covered drums 72 and 74, the rolls 66 and 68 are advantageously fabricated to possess a peripheral surface that is easily wet by water. This objective can be achieved by making the fountain rolls from a suitable stainless steel and by insuring a clean surface on the rolls. Preferably, the surfaces of the fountain rolls are made metallurgically clean by degre-asing them using pumice and then etching them with a phosphoric acid solution. However, the action of the flexurally resilient elements 78 in the presence of water serves to clean the fountain rolls and keep them clean in adequate manner. The fountain rolls 66 and 68 are provided with stub shaft elements 1436, as is shown in FIG. 8, for purposes of journalling and drivingly rotating these rolls.

In compliance with a feature of the invention, each fountain roll and its corresponding dispensing drum are driven in opposite rotational directions, as is shown by arrows in FIG. 8; and the drum is driven at a faster speed than the corresponding fountain roll. Therefore, the drums and fountain rolls are power operated through a suitable transmission. As is shown in FIG. 3, an electric motor 108 is employed as the power source; and rotational energy is delivered from the motor 108 to an operating shaft 110 by means of a speed reducing belt-andpulley arrangement 112. The means which are employed in the illustrated embodiment for transferring power from the operating shaft 110 to the dispensing drums 72 and 74 and to the fountain rolls 66 and 68 will now be described with reference to FIGS. 4-6. There a pinion gear 114 is affixed to the operating shaft 110 for meshed engagement with the first of two intermeshing spur gears 116, spur gears 116 being rigidly mounted, in turn, to the shafts lilil of the drums 72 and 74. Intermes-hing of the spur gears 116 insures the driving of drums '72 and 74 in opposite rotational directions.

With particular reference to FIG. 6 and in compliance with a feature of the invention, the shafts 1669 are seen mounted for vertically adjust-ably resilient movement in spring-bias arrangements 118. Each of the arrangements 118 includes a journal block 120 that rotatably receives the corresponding shaft 196 and that is slidably operable in a vertical slot 122, slots 122 being fashioned in one of two spaced end plates 12 i. Compression springs 126 are situated between the blocks 12% and the floors of the slots 122 in order to support the shafts 160 resiliently. The upward movement of each block 120 is limited by a screw element 128 which threadedly engages a bore formed in a plate 130 superpositioned over the slot 122. Screw element 128 abuttingly contacts the corresponding block 126. i

In order to coordinate the rotation of the fountain rolls 66 and 68 with their respective dispensing drums, at geared interconnection is provided at the opposite end of the respective members, as is shown in FIG. 5. There, a pinion gear 132 is mounted on one of the shafts 100 to mesh with the first of two intermeshing gears 134. The last of the two gears 134 meshes with a spur gear 136 which is mounted on a shaft 166 and which meshes, in turn, with a second spur gear 138. Spur gear 138 is of the same size as spur gear 136 and is mounted on the other shaft 166. By this arrangement, the fountain rolls are driven in opposite rotational directions with respect to each other and with respect to the corresponding dispensing drums. In addition, the gears 132, 134 and 136 achieve a speed reduction whereby to drive the fountain rolls at a slower speed than the dispensing drums; and advantageously, the speed of the dispensing drums is arranged to be at least about four times the speed of the corresponding fountain roll and as much a eight times the speed thereof. By arranging the dispensing drums to rotate at a greater speed than the corresponding fountain rolls and in the opposite rotational direction, effective dispensing action of the resilient elements 76 in spattering the Water from the fountain rolls is insured. Spring-bias mounting arrangements 118 are also provided at the ends of the shafts 100 which are adjacent the gears 136 and 138.

In accordance with another feature of the invention, the bristle elements are arranged for disposition in transiently interfering engagement with the associated fountain roll in the vicinity of the dispensing region 70. With reference to FIG. 8, the several elements 76 are arranged with an interference i which is at least about one-fourth the length of the elements 76 and desirably at least about one-third thereof. Thus, when the elements 76 are nylon bristles having a length of approximately three quarters of an inch, the interference i will be about one quarter of an inch.

Having thus described one construction of the invention, it is important now to state how the illustrated embodiment operates. Assuming that the printing sysem is in operation at ordinary running speed and considering FIGS. 7 and 8, it will be apparent that the web 24 will be moving continuously past the dispensing region '70. Assuming further that the motor 103 is suitably energized to drive the fountain rolls and their corresponding dispensing drums in the directions indicated by the arrows in FIG. 8, the rotating fountain rolls 66 and 68 will pick up a film of water on their peripheral surfaces to deliver the same to the resilient elements 76 at the area where the elements 76 engage the corresponding fountain rolls. As has been described, the relative directions of rotation and the relative speeds of the dispensing drums and the fountain rolls will cooperate'in causing the resilient elements 76 to sweep through the film of water carried by the fountain rolls and out of engagement with the peripheral surfaces of the fountain rolls. As the elements 76 are released from engagement with the fountain rolls, their resiliency will tend to restore them to their substantially radial position whereby to jet a band of fine droplets 14!} onto the moving web. Because of the multiplicity of the elments 76, a dense and uniform pattern of droplets is spattered onto the Web 24 as is shown in FIG. 9. 1

Because of the fountain rolls and their associated dispensing drums are arranged in cooperating pairs on opposite sides of the web 24, the web is moistened evenly, thus avoiding objectionable curling which might arise because of not Wetting the Web equally on both sides. It is also important to observe that the resilient elements 76 do not contact the web 24 and thus do not impede its motion or present a possibility of smearing or streaking the applied moisture. dampening apparatus 36 with the chill rolls 54, the moisture is applied to a still-warm Web which thereby tends to absorb and distribute the moisture uniformly throughout its fibers. The moisteni-ng of the web 24 which is achieved by means of the dampening apparatus 36 restores the toughness and and strength of the web; and high speeds of operation can be achieved when the dampening apparatus is utilized. In one practical embodiment of the invention, use of the dampening apparatus, as compared with non-use in the same printing system, permitted an increase in the speed of operation of from about 10 to 15 percent; and in some instances, use of the dampening apparatus allowed an increase of as much as percent in the speed of operation. Moreover, it has been found that machine coated (enamelled) papers are susceptible to cracking when highly desiccated; and rela tively heavy paper stocks must be employed when a drying oven procedure is necessary. Use of the apparatus of the invention eleminates the need for increasing the weight of the paper stock. In a partical embodiment of the invention, 70 pound coated and 60 pound uncoated paper were necessary or successful operation without the dampening apparatus, but use of the dampening apparatus permitted a reduction in the stock weight to -45 pound uncoated and -50 pound coated stocks, thereby achieving substantial economies in the printing operation.

It has also been found possible to add wetting agents or humectants such as glycerin to the water in the trays 78 and 80. Furthermore, the addition of an electric heater, such as the electrical heater arrangement 142 shown in FIG. 8, has been found to be useful in elevating the temperature of the dispensed liquid. This heating of the water that is to be dispensed has proved to achieve somewhat better penetration and is advantageous when it is necessary to separate the dampening apparatus from the chill rolls by some substantial distance. Utilization of suitable controls for coordinating the driving of the fountain rolls and the dispensing drums in accordance with the speed of movement of the web 24 is contemplated whereby to regulate the amount of added moisture and whereby to avoid overwetting of a discrete region of the web in the event of a temporary shutdown.

The specific example herein shown and described is to be considered as being primarily illustrative. Various changes beyond those described will, no doubt, occur to those skilled in the art; and such changes are to be understood ias forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows: I

1. In apparatus for printing a continuous web, the combination comprising: roll means for directing a web in a vertical path of movement; a water reservoir including Due to the proximity of the- "r t, a pair of elongated trays spaced laterally on opposite sides of said path to accommodate said Web therebetween and further including connection means coupling said trays beneath the water level thereof and adjacent corresponding ends thereof spaced from the edge of said web whereby to preserve a uniform water level in said trays; a pair of rotatable cylinders associated with said reservoir and arranged individually with said trays, each of said cylinders being disposed partially Within the corresponding tray for receiving a film of water therefrom and partially extending from the corresponding tray for presenting the film of water at a dispensing region; a rotatable cylindrical member operatively associated with each of said cylinders, said member being aligned with its longitudinal axis parallel to the longitudinal axis of the corresponding cylinder, said member having a multiplicity of flexurally resilient bristles mounted thereon to extend substantially radially therefrom for disposition in engagement with the corresponding cylinder at said dispensing region; and drive means for said cylinders and for said members operative to rotate said members rela- 'tive to said cylinders whereby to sweep said bristles through said film of water and out of engagement with said cylinders for spattering a stream of droplets evenly onto both sides of said web.

2. In apparatusfor printing a continuous web, the com bination according to claim 1 wherein said bristles are of a substantially uniform, predetermined length and wherein the spacing of the axes of said member and the corres ponding cylinder is arranged to establish an interference between said bristles and cylinder of at least one-fourth of said predetermined length.

3. In apparatus for printing a continuous Web, the combination according to claim 1 wherein said member is rotated at a speed of at least about four times the speed of the corresponding cylinder.

References Cited by the Examiner UNITED STATES PATENTS 2,648,088 8/53 Bailey 68200 X 3,158,886 12/64 Grimes 13464 FOREIGN PATENTS 1,193,816 11/59 France 165,553 11/05 Germany.

654,506 12/37 Germany.

921,664 12/54 Germany.

346,671 7/60 Switzerland.

25 CHARLES A. WILLMUTH, Primary Examiner. 

1. IN APPARATUS FOR PRINTING A CONTINUOUS WEB, THE COMBINATION COMPRISING: ROLL MEANS FOR DIRECTING A WEB IN A VERTICAL PATH OF MOVEMENT; A WATER RESERVOIR INCLUDING A PAIR OF ELONGATED TRAYS SPACED LATERALLY ON OPPOSITE SIDES OF SAID PATH TO ACCOMMODATE SAID WEB THEREBETWEEN AND FURTHER INCLUDING CONNECTION MEANS COUPLING SAID TRAYS BENEATH THE WATER LEVEL THEREOF AND ADJACENT CORRESPONDING ENDS THEREOF SPACED FROM THE EDGE OF SAID WEB WHEREBY TO PRESERVE A UNIFORM WATER LEVEL IN SAID TRAYS; A PAIR OF ROTATABLE CYLINDERS ASSOCIATED WITH SAID RESERVOIR AND ARRANGED INDIVIDUALLY WITH SAID TRAYS, EACH OF SAID CYLINDERS BEING DISPOSED PARTIALLY WITHIN THE CORRESPONDING TRAY FOR RECEIVING A FILM OF WATER THEREFROM AND PARTIALLY EXTENDING FROM THE CORRESPONDING TRAY FOR PRESENTING THE FILM OF WATER AT A DISPENSING REGION; A ROTATABLE CYLINDRICAL MEMBER OPERATIVELY ASSOCIATED WITH EACH OF SAID CYLINDERS, SAID MEMBER BEING ALIGNED WITH ITS LONGITUDINAL AXIS PARALLEL TO THE LONGITUDINAL AXIS OF THE CORRESPONDING CYLINDER, SAID MEMBER HAVING A MULTIPLICITY OF FLEXURALLY RESILIENT BRISTLES MOUNTED THEREON TO EXTEND SUBSTANTIALY RADIALLY THEREFROM FOR DISPOSITION IN ENGAGEMENT WITH THE CORRESPONDING CYLINDER AT SAID DISPENSING REGION; AND DRIVE MEANS FOR SAID CYLINDERS AND FOR SAID MEMBERS OPERATIVE TO ROTATE SAID MEMBERS RELATIVE TO SAID CYLINDERS WHEREBY TO SWEEP SAID BRISTLES THROUGH SAID FILM OF WATER AND OUT OF ENGAGEMENT WITH SAID CYLINDERS FOR SPATTERING A STREAM OF DROPLETS EVENLY ONTO BOTH SIDES OF SAID WEB. 